costly

adjective

cost·​ly ˈkȯs(t)-lē 

costlier; costliest

1

a

: commanding a high price especially because of intrinsic worth

costly gems

b

: rich, splendid

2

: made or done at heavy expense or sacrifice

a costly mistake

costliness noun

Synonyms of costly

• expensive
• valuable

Examples of costly in a Sentence

We use less costly materials in our products.

It was too costly to fix her car after the accident, so she decided to buy a new car instead.

They won the game, but their best player was injured, so it was a costly victory.

The decision to wait could be a costly mistake.

Recent Examples on the Web

Los Angeles Lakers star Luka Doncic is set to serve his suspension following a costly technical foul in the team's previous game, but that shouldn't hurt his chances at winning NBA Most Valuable Player. —Matthew Couden, MSNBC Newsweek, 31 Mar. 2026

For years, would-be first-time homebuyers have complained about the skimpy inventory of starter homes, saying costly McMansion-style subdivisions are all that’s being built now. —Don Stacom, Hartford Courant, 30 Mar. 2026

Locals rely on costly virtual private networks, or VPNs, to report events and send videos, meaning news often trickles out slowly. —ABC News, 30 Mar. 2026

But some financial advisors have expressed concerns that many 401(k) investors lack the knowledge or experience to incorporate these more sophisticated investments, which can be riskier and more costly. —Sarah Agostino,stephanie Dhue,greg Iacurci, CNBC, 30 Mar. 2026

Word History

First Known Use

14th century, in the meaning defined at sense 1a

Kids Definition

costly

adjective

cost·​ly ˈkȯs(t)-lē 

costlier; costliest

1

: of great cost or value

costly furs

2

: gained at great expense or sacrifice

a costly victory

costliness noun